1. In a bowl, mix 1/5 grams (1/3 teaspoon) of the yeast, 300 grams (2 cups plus 2 heaping tablespoons) of the flour, and the room-temperature water together until there are no dry bits; this is called the poolish, or starter dough. Place it in a container that will allow the mixture to expand three times in volume. Let rest, covered with a kitchen towel, at room temperature for at least 8 and up to 12 hours.

2. After this time, in a large mixing bowl, whisk together the remaining yeast with the milk, sugar, vinegar, and oil. Add the poolish to this mixture.

3. In a separate bowl, mix the remaining flour with the baking powder and salt. Using a wooden spoon, combine the dry and wet ingredients together. Cover with a kitchen towel and set aside in a warm spot to rise until more than doubled in volume, about 3 hours.

4. Turn the dough out onto a floured surface, and pat it down with floured hands until it’s about 1 inch thick. Use a 3 ¾-inch round cutter to cut muffins out of the dough. Place the muffins on a sheet pan that has been lined with parchment paper and dusted with cornmeal. Let the muffins sit for 10 to 15 minutes.

5. Ideally, cook the muffins on an electric griddle set to 350°F. If you don’t have one, set two large nonstick sauté pans or two cast-iron skillets over medium heat. Grease the cooking surface lightly with butter and dust it with cornmeal. Cook the muffins for 5 to 8 minutes per side, turning them when the first side is done—each side should be a deep golden brown. Stored in an airtight container at room temperature, the muffins will keep for a week.